We have previously suggested that insulin resistance is the basic defect leading to the development of endogenous hypertriglyceridemia. In an effort to further define the cause of the insulin resistance, we plan to study insulin binding to specific insulin receptors in hepatocyte, adipocyte and lymphocyte in various states of insulin resistance. These studies will be carried out in man and laboratory animal, and we will study primary insulin resistance, as well as insulin resistance secondary to uremia and adrenal corticoid administration.